Galileo Galilei (1564-1642)

     Galileo Galilei was an Italian physicist and astonomer who contributed greatly to the history of science and to modern society. He was a uniquely brillant man with a curious mind which led him to make many discoveries and to conduct experiments that have changed the world of science forever.
    Galileo was the son of Vincenzo Galilei of Florence who was a famous musician and Giulia degli Ammannati of Pisa. They were married July 5, 1562 and had their first child, Galileo, February 15, 1564. He was baptized in the bapistry of the cathedral of Pisa, February 19. The family lived in Pisa until they moved to Florence in 1574.
    Growing up, Galileo was extremely interested in medicine. He studied at the University of Pisa in 1581 but abandoned these interests for mathematics and physical science. He became a professor of mathematics at Pisa in1589-91 and at Padua 1592-1610 and he taught privately in Florence. He invented a " geometric and military compass" used to solve practical mathematics problems which he taught his students to use, along with writing an instruction manual on the compass.
    In the duration of these years, Galileo studied and experimented with mechanics, building a thermoscope which was used to conduct experiments on heat changes of different liquids.
    In May of 1609, he heard about a new invention of a device that was built to see objects from a great distance. Galileo then duplicated the invention, improving its strength and ability to magnify objects. From his design he made many observations such as mountains on the Moon in December 1609, four small bodies orbiting Jupiter in January 1610, sun spots in May 1612, and that the Milky Way is made of billions and billions of "tiny" stars. His investigations were rewarded with as appointment as a professor at the University of Florence. He also developped a device similar to a protomicrometer to mesure the diameters of stars and planets, along with a microscope that was made with a similar version of a tube of telescope, and furnished with two lenses. He also invevted the hydrostatic balance for measuring the specific gravity of solids.
    In 1613, he discovered that Venus showed phases similar to those of the Moon and therefore must orbit the Sun, not the Earth. Galileo was famous for his belief in the Copernican view of the Earth's position in the universe. The Copernican view is the arrangement of the planets where the Sun is the center of the Solar System, not the Earth. THis theory contradicted the Earth-centered Universe of Aristotle and Ptolemy, which was believed to be correct for almost two thousand years until the sixtenth century when the Polish astronomer Nicolai Copernicus proposed the idea of the Sun being the center of the Universe. The church believed in the Ptolemaic System, therefore rejecting Galileo's attempts to prove the old system wrong. When Galileo discoverred the phases of Venus, he proved that Venus goes around the Sun, supporting the Copernican System.
    Galileo also discovered ischronism of a pendulum and formulated the laws governing falling bodies, along with his many astronomic discoveries.
    In 1632, Galileo's health began to deteriorate and he became blind. He died in Arcetri on January 8, 1642.
    Despite being rembered for his many achievements and discoveries, Galileo will be loooked upon as a hero for fighting for what he believed to be true and for proving the Ptolemictheory wrong. He has left a great impact on the world of science and will be honored by people everywhere and a role model for many scientists.